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i tions, and it has for its bodies act found that the UNITED STATES PATENT OFFICE.

TA-HEB A. HoCOY, OI WILKINSBURG, PENNSYLVANIA, ASSIGNOB TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

PLASTIC COMPOSITION.

1,317,204. Ilo Drawing.

To all whom it may concern:

Be it known that I, JAMES P. A. MCCOY, a subjectof the King of Great Britain, and a resident of VVilkinsbur in the county of Allegheny and State of ennsylvania, have invented a new and useful Im rovement in Plastic Compositions, of whic the followin is a specification.

y invention relates to lastic composiject to prepare plastic compositions from varnish as shellac, copal, and the like which are rittle and must ordinarily be handled in alcoholic or oil solutions. Y

I have discovered that certain varnish ms, notabl shellac, may be rendered flexi is or even fl ilid by the addition of naphthalene, naphthols or derivatives of these bodies other than chloro-naphthalene. The naphthalene as solid solvents for the shellac, and, when very volatile naphthalene bodies are used, such as naphthalene itself, shellac can be made to flow when heated, the liquid being almost as mobile as water. The mixture of shellac and naphthalene or naphthalene derivatives other than chloro-naphthalene may be used with advantage for many pur oses. 4

T e foregoingmethod of treating shellac and other gum facilities their use as a nts for impre ating fibrous material suc as paper, clot and the like. Paper and cloth impregnated with shellac are largely used for electrical insulating urposes and imregnating liquids for t is pur ha e heretofore been made either by mixing shellac with oil, which is a diflicult matter, or'by. dissolving the shellac in wood alcohol. The latter practice is usually followed, and it is presence of wood alcohol, which can be completely removed from the shellac only with great difliculty, lessens the dielectric strength of the ,product.

Shellac-naphthalene mlxtures pre ared in accordance with m invention may e re- .duced to liquid form by simple heating, and paper, cloth and other absorbent materials may be readily impregnated with the resulti liquid. If desired, the fabric may be sii jected to heat treatment after bein imregnated, in order to remove the nap thalene body either partly or entirel Another valuable a plication 0 mixtures of shellac with napht alene, naphthols and.

' other than chloro-nap I Specification of Letters Patent. Patented Sept, -30, 1919, Application filed April 12, 1915. Serial No. 20,750

the like is in the manufacture of flexible built-up mica sheets and molded micaarticles. For this purpose, shellac and naphthalene may be ground together or ma be ground separately and then mixed, and the resultin powder used as a bond for uniting 80 mica fla es, by means of any usual or convenient mica-buildin a paratus;'or a similar bond may be made y first pre arin a solid solution of naphthalene and shefiac and then grinding the solid mass to powder without the application of heat. Composite mica sheets repared with either of these binders may e finished by placing them for a short time between heated plates or in heated molds, and it is found that the resulting product is distinctly flexible and is thereby distinguished "from the built-up mica bodies that have heretofore been made. Inert materials other than mica may be agglomerated by meansof my shellac-naphthalene binders, and flexible compositions thereby produced. Asbestos, silica and wood flour are examples of filling materials that may be so used. I

he roportions in which shellac and one or naphthalene derivatives thalene may be mixed together may be varied within wide limits. One mixture with which I have obtained good results in preparing flexible mice 86 plates is composed of substantially 90% of shellac and substantially 10% of naphthalene; The; mica plates or other bodies prepared with this mixture as a binder should e heated only suflicientl to thoroughly 90 melt the binder-and unite t e flakes, because lon er heating will expel som orrall of the nap thalene and will consequently impair the flexibility of..the product. i

If (permanently flexible products are require I prefer to use naphthols or other naphthalene derivatives rather than naphthalene itself, sincethey are not volatilized from the shellac on heating. Such products may be repeatedly heated and cooled without losing their flexibility.

It is obvious that the products which 1' have discovered may be used for many other purposes than those which Ihave s cifically mentioned, and it is therefore to g un- 106 derstood that my invention comprehends all such modifications and adaptations {as fall within the scope of the appended claims.

naphtha I claim as my invention: 4. A plastic composition comprising shel- 1. A plastic composition comprising shellac, mica flakes and naphthalene. lac and naphthalene. In testimony whereof, I have hereunto l0 2. A plastic composition comprising la subscribed my name this 30th day of March, natural varnish gum and naphthalene. 1915.

3. A plastic composition comprising shel- Inc. a filler, and naphthalene. JAMES P. A. MCCOY. 

